Toggle press



July 18, 1944- J. F. JOHNSON, sn 2,354,12 TOGGLE PRESS 3 Sheets-Sheet 2 Filed April 21, 1942 v July 18, 1944# J. F. JOHNSON, sR 2,354,126

TOGGLE PREss Filed April 21, 1942 3 sheets-Sheet 5 Patented July 18, 1944 TES ,sans

yto Triumph Explosives, Inc., Elkton, Md., a

corporation of Maryland Appiicaeon April 21, 1942, serial No. 439,941

(C1. afi-30) 8 Claims.

This invention relates to presses and more particiuarly to presses of the limited or predetermined pressure type. VIt is a general object of the present invention to provide a novel and improved press having means to prevent the application thereby of pressure beyond a, predetermined fixed limit under any. conditions.

More (particularly it is an object of the inventionr to provide a press of the manually operated type in which a toggle is used to exert pressure on aA plunger and" in which the abutment for the opposite end of the toggle is movable upon excess applied pressure.

Another important object of the invention comprises the arrangement of the press anvil and plunger withina compartment having a single open side together with a door adapted to be closed automaticallyv before the application of pressure to said plunger and opened only subsequent to the release of such pressure whereby work may be done on explosive materials with complete protection for the operator.

Other and further features and objects of the invention will be more apparent to those skilled in the art upon a consideration of the accompanying drawings and following specication wherein is disclosed a single exemplary embodiment of the invention with the understanding that such changes, rearrangement of parts and the like may be made therein as fall within the scope of the appended claims without departing from the spirit oi the invention.

In said drawings:

Figure 1 is aside elevation of the press showing in solid lines the parts in pressing position and in dot and dash lines the parts in retracted position;

"Figure 2 is a front elevation of the press with the parts shown in pressing position;

FigureY 3 is a horizontal section taken on the plane of line 3 3 of Figure 1 looking downwardly;

Figure 4 is a fragmentary vertical section on theplane of line `4-4 of Figure l;

Figure 5 is a fragmentary vertical central section taken on the plane of line 5 5 of Figure 2;

Figure 6 is a fragmentary front elevation, partly in section, of the main shaft assembly; and

Figure '7 is an elevation, partially in'section of a spring gauge for use with the press.

In a, great many industrial processes there is ing material andthe like, and these needs have 'need for a press for assembling parts, compactheretofore been met iby both hand and power presses of various sorts. In a great many oprations some pressure in excess of that necessary to carry out the normal pressing operation is not detrimental, and if the press is only slightly over-powered no harm can result in the case where an over-sized article, a poor fit, an excess quantity of material tobe compressed or the like, iinds its way beneath the press plunger and thus limits the plunger stroke to less than normal. In some cases, however, this excesspressure is not only detrimental butV is dangerous.

In the loadingr of explosive charges such as detonators and similar devices, it is extremely important, and usually mandatory in accordance with specications, to apply a very definite pressure just adequate to provide the essential compacting of the pulverulent material in order to regulate to a desiredrate the" llame propagation through the same. Excessive @pressure may result in improper operation of the article `so treated or may result in its immediate explosion while under the press. Insuicient pressure might so loosely compact the material as to seriously interfere in one way or another with the operation of the finished product. To avoid these several diniculties it is proposed, according to the present invention, to provide a press suitable for manual or power operation in which pressure is always up to a predetermined value but cannot be in excess of this or a slightly higher predetermined value in spite of continued application of power from any source. The press is made so that the limits may be readily adjusted in accordance with the requirements.

In spite of all the care used and the above limitations |placed on the pressure which can be applied, certain sensitive detonating agents occasionally explode while being compressed and in order to safeguard the operator and the associated equipment, to prevent iire and to improve the morale of the personnel, it is essential that the article being pressed be fully enclosed in a sturdy all-metal chamber of suilicient size to absorb,the gas expansion resulting from an explosion without producing excessive pressure on the chamber walls. The opening and closing of the chamber for the purpose of loading and unloading the press must be entirely automatic and out of the control of the operator so that it is impossible to press a detonator with the chamber open or to open the chamber until the pressure has been relieved. In accordance with the present invention mechanism for handling this situation is incorporated with the @pressure limiting means.

Referring now to the drawings wherein is illustrated, for the sake of convenience, a manually operated press designed particularly for loading small detonator tubes, there is shown at I'U a base of heavy cast metal arranged to be secured to a bench, table or the like in any desired manner and including some means for locating, in accurate register with the plunger of the press, the article to be treated therein. In the present instance the detonator comprises a small tube which is charged with one or more batches of priming material. The detonator tube is held during operations thereon in a recess I I in a fixture or jig I2 of cylindrical form which is conveniently received in a shallow recess I3 in the base I which serves to hold the same in vertical position and in proper registry with the plunger I4 of the press which will be later described.

Above and parallel with the base I0 is a corresponding heavy plate I5 integrally. connected to the .base by suitable frame members IB and serving to form the top wall of a compartment of which the base is the bottom. Heavy metal plates I1 are suitably bolted to thel edges of the parts I0 and I5 to form the side and rear walls of a relatively large chamber I8 enclosingy the base and the operating portion of the plunger. The front of the chamber is not provided with a permanent closure but vertical guide Ways in the frame parts I6 accommodate a vertically slidable front door 22 of suitable heavy sheet metal. This door is prevented from being blown forward by the guides just described as wellas the flange 23 extending upwardly from the base Ill and behind which the door rests when closed.

Extending upwardly from the plate I5 and preferably formed integral therewith are a number of frame parts including the broad central upright 25 which, together with the central forward post 28, supports the horizontal platform 29 which is thickened vertically to provide an upper guide for the plunger I4, the lower guide comprising the bushing 3| in the plate I5. The elongated plunger is thus adequately maintained in alignment by widely spaced slide bearings. Its lower end is suitably reduced in diameter as at 32 to cooperate with fitting I2.

Vertical reciprocation of the plunger and the application of the requisite pressure thereto is effected through the agency of a hinged toggle, the lower section of which is composed of a pair of widely spaced link members 33, the enlarged lower ends of which are transversely bored toreceive the pin 34 pivoting them to the plunger I4 intermediate its length and its engagement with the guides. The upper portion of the toggle comprises the two link members 3B, the lower ends of which are fitted between the upper endsofthe members 33r as clearly seen in Figure 2. The upper ends of the links 36 are spaced apart just suiliciently to straddle the lever 31 to which they are pivoted by the cross pin 38k which intersects the axis of reciprocation ofthe plunger. This lever 31 which `comprises a movable abutment for the upper end of the toggle has its forward end pivoted on the transverse pin 39 at just a short distance forward of the pinv38, this latter pin being carried by the fitting 40 adjustably attached to the column 29 by means of vertical bolts 4I andvnuts and lock nuts 42 for taking the vertical thrust. The fitting 40 is rigidly attached t0 the the detonator tube in the column, after adjustment by the nuts 42, by means -of the clamping studs 43.

The overlapped intermediate ends of theV two sets of toggle links straddle the forward end of a substantially horizontal power applying link 45 and the whole assembly is hinged together by a pin 45 as clearly seen in Figures 1 and 3. Upon the application of a suitable force axially of the link 45 the toggle can either be straightened or broken as shown in solid lines and dot and dash lines in Figure 1.

If it happens that the fixture I2 is improperly positioned in the recess in the base, if there is too much material in the tube being loaded, or if other reasons prevent the plunger I4 from reaching its lowermost position when the toggle links are in alignment, without the'application of pressure beyond that desired on the material, then the continued application of force to the link 45 tending to straighten the toggle will be relieved by the'lifting of the abutment end 38 of the toggle which will result in rotating thelever 31 about its pivot 39 in a counter-clockwise direction. Such rotation is resisted by the helical tension spring 50, the upper end of which is attached to the lever by being hooked into a notch 5I near the free end thereof. The lower end of the spring is secured to a hook 52, the shank 53 of which passes through a horizontal plate 54 forming a portion of the machine frame. The threaded lower end of the shank receives a lock and lock nut 55 for adjusting the spring tension.

In order that the lever 31 may have a predetermined initial spring tension applied to it without moving it beyond the desired horizontal position, its free end is supported between the arms of a forkV 56 attached to the upper end of a vertical post 51 mounted on the plate 54. 'I'he spring 50 draws the right-hand end of the lever down against this post providing an initial restraining force which when overcome by the action of the toggle permits the lever to be lifted to relieve the strain on the press plunger as will be appreciated. By adjusting the spring tension and the position of the pivot 39 the maximum pressure .exerted by the press under any set of conditions can be accurately and closely adjusted.

Extending upwardly from the plate I5 substantially in alignment with the rear wall of the compartment I8 are the frame columns 60 suitably webbed and reinforced as by attachment to the column 25 through the inclined member 6I. These columns each support at their upper ends integral bearing bosses 62 in horizontal bores of which is journalled the main shaft 6.3. This extends beyond the right-hand bearing and receives thehub 65 of a hand crank 66 provided with the handle 61. It also receives the hub 68 of an arm 69 carrying at its outer end a. suitable counterweight 10 which may be integral therewith. A relative angular disposition of the crank arm and the weight arm 69 are illustrated in Figure 1.

Mounted on the shaft 63 between the bearings 62 is a crank assembly including the spaced arms 12 having hubs 13 attached to the shaft and supporting a crank pin 14. The spaced arms 12 receive between them and journalled on `the pin 14 the rear end-of the toggle actuating link 45 previously mentioned. It will be noted that `when thehandle of the machine is ai; its uppermost dot and dash line position as lshown in Figure 1, the toggle is broken and the plungerV lifted to its maximum extent. The lever is then in a convenient position for the operator to grasp and swing forward through about 135 to the solid line position which straightens the toggle and applies pressure to the plunger. The latter part of the plunger stroke involves a downward movement when the operator can conveniently apply his weight during the nal pressure stroke. During this time a counterweight 'lil moves from a low position illustrated in dot and dash lines in Figure i to a substantially vertical position and assists by its momentum in the pressing operation. Normally the counterweight 1D maintains the plunger and crank handle in their upward positions, with the toggle broken, as shown in broken lines in Figure 1.

The crank arms travel only in the upper segment of the crank pin circle. The counterweight is so disposed that when in its lowermost position it exerts nearly its maximum effort and retains the plunger in the lifted position. It may either be provided with a suitable stop or reliance may be had on the link l5 resting on the hub 16 which is mounted between the hubs 13 as clearly seen in Figure 1. No limit stop for the forward movement of the toggle actuating link is required since if the toggle breaks in the forward direction no harm is done and pressure is relieved but such as stop may readily be applied if desired.

In order to operate the door I1 there is provide a tilting lever 80 the forward end of which is attached to the door by a flexible strap 8| as clearly seen in Figures l, 2 and 5. This lever .is oifset from the central plane of the press so that it passes to one side of the column 28 and has the bent forward end 82 to which the strap 8| is attached. 'I'his lever is fulcrumed at 84 on a pin attached to one of the columns 69 liust below the shaft 63 and the rear end of the lever is fitted with a counterweight 85 which may be adjusted along its length and secured in position by locking screws SG. The mass and lever arm of the weight are such that it does not over-balance the door. Under these conditions the door by its own weight always remains closed unless it is positiveli7 moved to an open position. Such opening action is effected by a roller 81 mounted on a pin 88 secured in the head 89 of an arm 99 extending radially from the hub 15 previously mentioned as forming a stop for the link G5. This roller 81 moves from the dot and dash line position to the right of shaft 53, and in engagement with the dot and dash line position of the lever SB in Figure l. to the position shown just behind the solid line eounterweight arm 69 in Figure 1. The roller does not show in solid lines in this View because it is always behind the counterweight arm.

As seen in Figure l, when the parts are in the dot and dash line positions with the plunger elevated, the roller 81 engages the top surface of the lever 80 behind its pivot 84, but not a great distance therefrom, and holds the door open for convenience in loading the work into the chamber i3. The first small fraction of rotational movement of the operating handle 61 removes the roller 81 from contact with the lever 80 and permits the door to fall of its own weight with great rapidity before any substantial movement is given to the plunger. The door is therefore insured of being closed before the plunger engages the work or applies any pressure to the same. Conversely the plunger is well lifted and entirely clear of the work before the roller 81 again engages the door lever to lift the same.

This lifting occurs in the same small fraction of rotation'of the main shaft that occupied rthe closing of the door.

In order that the operatorof the press may be able to judge at all times the exact amount of pressure being applied by the press, under normal conditions, the spring 50 shown in Figure 1 may be replaced by the spring gauge combination shown in Figure '1. This comprises a tubular barrel |00 closed at the upper end by a cap ill! perforated at |02 to slidably receive the tension rod |03, the upper end of which is equipped with a bifurcated fitting |66- pivoted at |05 toA the right lhand end of the lever 31 which provides the anchorage for the upper end of the toggle links.

The tube |00 is provided with a bottomcap IGS having an integral perforated lug |01 in the aperture |08 in which is received the hook on the end of the rod 52. For convenience in adjustment, the nut and lock nut 55' may be equipped with wings for manual operation.

An open type coil spring 50 loosely housed in the sleeve Ill!) has its upper end abutting against the cap IUI and its lower end abutting against a head Il! securely attached to the lower end of the tension rod |133 whereby upon upward movement of the lever 31 the spring is compressed between this head and the tube' head lill. The tube is slotted longitudinally as at ||2 to accommodate the indicator H3 which is in the form of a small screw horizontally slotted and fastened into the head Htl. Graduation marks H5 appear alongside the slot ||2 and each is appropriately marked with indicia in pounds or the like to designate the pressure being applied at the time. It :is obvious that these markings will not designate the direct pressure exerted by the spring but rather the pressure at the press plunger where the tension of the spring is multiplied by the ratio of the lever arm 38, 39 to the lever arm 38, |05.

To set the spring for the desired plunger pressure it is only necessary to position a work piece beneath the plunger, move the handle 51 until the toggle 33, 36 is straight, and adjust the nut 55' until the pointer i3 coincides with the desired pressure as indicated on the scale, when the lock nut can he set to maintain the adiustment.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent isz.

1. In a press for compacting explosive materials, in combination, a base, an explosive proof chamber on said base, a frame extending upwardly from the base and providing a vertical guideway, a pressure exerting plunger reciprocable in said way and penetrating said chamber to cooperate with work resting on said base, a lever pivoted to said frame at a point just forward of the axis of reciprocation of said plunger, a support on saidl frame having a forked upper end to receive the opposite end of the lever and support the same horizontally, a spring engaging the free end of the lever and adjustable to tension said lever end into said fork, a pair of hinged toggle links, one having its lower end pivoted to said plunger and the other having its upper end pivoted to said lever at the intersection of the plunger axis therewith, a link pivoted to said toggle hinge and extending generally horizontally, a shaft journaled in frame parts on a horizontal axis transverse to that of said link, a crank on said shaft having a crank pin engaging said link, a hand crank on said shaft adapted to move outside of said frame, anda counterweight attached to said shaft and angularly positioned thereon to normally hold the'same in toggle breaking position whereby the plunger is raised.

2. In a press of the type described, in combination, an anvil and a plunger, means mounting said parts for relative movement for exerting pressure, walls forming a chamber about said parts open at one side, a door movable by gravity to close said open side, operating mechanism adapted to provide said relative movement and pressure, and means associating said mechanism and door for releasing the latter during an initial small fraction of the total movement of the former required to apply said relative movement and pressure, said means being so constructed and arranged as to open said door only during-'said small fraction at the end of the plunger retraction movement, the releasing and opening means being totally disconnected from the door at all times between release and opening.

3. In a press of the type described, in combination, an anvil, walls` forming a compartment about said anvil open at one end, a door vertically slidable to close said end, a plunger reciprocable through the top wall of said compartment to act on work on the anvil, a hinged toggle extending between an abutment and said plunger, av thrust link having one end pivoted to the toggle hinge, a main shaft, ahand lever for oscillating said shaft, a crank on said shaft connected to the opposite end of said link, a lever flexibly connected with said door, means pivoting said lever intermediate its ends, a roller movable with said shaft to engage said lever beyond the pivot from the door to open the door, a second lever, said abutment being located on said second lever, a fixed pivot for said second lever, and means to apply a predetermined load to said second lever to resist movement of said abutment.

4, In a press of the type described, in combination, an anvil, walls forming a compartment about said anvil open at one end, a door vertically slidable by gravity to close said end, a plunger reciprocable through the top wall of said compartment to act on Work on the anvil, manual means to raise said plunger or lower the same and apply pressure, resilient means arranged to limit the total pressure exerted by said plunger in spite of the power exerted by said means, and

mechanism being entirely separatedr from the door during the pressing operation.

5. In a press for compacting explosive materials, the combination Awith a supporting frame, press members on said frame an explosion proof chamber carried Aby said frame, in cooperative relation said press members coming into pressing relation within said chamber, operating means for` imparting reciprocating movement to one of said members, said operating means including a toggle acting between the moving member and a movable abutment, means to straighten or break the toggle including a. momentum member, and means to resiliently resist movement of the abutment with a predetermined minimum force.

6. In a press for compacting explosive materials, the combination of an explosion proof chamber a reciprocable pressure-exerting plunger penetrating said chamber, a movable abutment, toggle levers connecting said plunger and door operating mechanism associated withv said manual means, said mechanism being arranged to release the door before the plunger exerts any pressure, said mechanism being also arranged to open the door only after the plunger has been disengaged from the work, the door opening abutment, means to straighten the toggle to apply pressure to the plunger, resilient means to resist movement of the abutment, means to adjust said resilient means to predetermine the maxirnum pressure exertable by the plunger, and means to indicate the pressure exerted by the plunger when the toggle is straightened.

, 7. In a press for compacting explosive materials, the combination with a supporting frame, press members on said frame an explosion proof chamber carried on said frame in cooperative relation said press members coming into pressing relation within said chamber, operating means for imparting reciprocating movement to one of said members, said operating means including a toggle acting between the moving member and a movable abutment, means to straighten or break the toggle including a momentum member, means to resiliently resist movement of the abutment with a predetermined minimum force, and means to predetermine said minimum force.

8. In a press for compacting explosive materials, the combination of an explosion proof chamber, a reciprocating, pressure-exerting plunger penetrating said chamber, a pair of toggle links one of which is associated with said plunger, said links being adapted to be substantially aligned to move the plunger to the maximum pressure position, an abutment for the other toggle link, resilient means positioning said abutment Whereby the pressure exerted by the plunger is limited, and means to measure the pressure exerted at said abutment.

JOHN F. JOHNSON, SR. 

